Preparation of basic lead salts of 2:4 dinitro resorcinol



Patented Jan. 3, 1950 PREPARATION OF BAS IC LEAD SALTS OF 2:4 DINITRO RESORCINOL Leon Rubenstein, Saltcoats, Scotland, assignor to Imperial Chemical Industries Limited, a corporation of Great Britain N0 Drawing. Application uly 8, 1947, Serial No. 759,703

In Great Britain September 4, 1946 The present invention is concerned with an improved process for the manufacture of substantially monobasic lead salt of 2:4 dinitroresorcinol and has for its object to provide a substantially monobasic lead salt of 2:4 dinitroresorcinol in a condition of improved suitability for use in electric fuseheads and similar electric igniters.

The basic lead salts of polynitro phenolic compounds are made by a double decomposition reaction, usually carried out at substantially raised temperatures, between a solution of a soluble normal lead salt, e. g. lead nitrate, and a solution of the polynitro phenolic compound containing an excess of a soluble base, all in molecular quantities corresponding to the basicity of the basic lead salt required. The composition of the basic lead salts of polynitro phenolic compounds, however, is liable to vary considerably in accordance with the conditions under which they are pre:

pared, and the product that is precipitated as a result of the interaction between the solutions used frequently comprises a mixture of chemical individuals of varying basicities, while marked variations in quality are often experienced even when the lead contents of the preparations of any particular basic lead salt of a polynitrophenolic compound prepared under the differing conditions are the same. The lead contents of the basic lead salts obtained when even slight variations are made in the method of preparation are liable to differ quite appreciably, but variations in the requisite properties may occur even if the lead contents are the same, while on the other hand products of appreciably differing lead contents may be equally serviceable.

The substantially monobasic lead salts of 2:4 dinitro-resorcinol as prepared by precipitation in the usual manner by the addition of a solution of 2 mols lead nitrate to a solution of 1 mol disodium salt of 2:4 dinitro-resorcinol and 2 mols sodium hydroxide at raised temperature when washed'free from soluble salts and dried may contain from say 59 to 69% lead, and their easy ignitability when heated and excellent deflagrating characteristics would render them very suitable for use in electric fuseheads and similar electric igniters as the ingredient in the deilagrating bead or the like directly ignitable by the electrically heated conductor. They have, however, a marked tendency to gelate nitrocellulose solutions, and since the deflagrating bead or the like is ordinarily built up by alternately applying and drying oil successive coats 6 Claims. (01. 266 435) of a suspension of the ignitable ingredient in a viscous solution of nitrocellulose in a volatile gelate nitrocellulose solutions is obviated if in a process for the production of a substantially monobasic lead salt of 2:4 dinitroresorcinol wherein a solution of a soluble normal lead salt is caused to react with an alkaline solution of 2:4 dinitroresorcinol at raised temperature, the precipitate of substantially monobasic lead salt of 2:4 dinitroresorcinol is treated with a small amount of an acid that has a soluble lead salt added gradually in a dilute state before the precipitate is washed free of soluble salts. 7

According to the present invention the process for the production of a substantially monobasic lead salt of 2:4 dinitroresorcinol in which are included the steps of forming a precipitate of this lead salt by reacting a solution of a sol- 'uble normal lead salt with an alkaline solution of 2:4 dinitroresorcinol at raised temperature and subsequently washing the precipitate thus formed free. from soluble salts comprises gradually adding a small amount of a dilute solution of an acid that has a soluble lead salt to the said precipitate prior to the said washing.

Preferably the acid having a soluble lead salt is introduced dropwise into the liquor containing the precipitate or suspension of the monobasic lead salt of 2:4 dinitroresorcinol and the by-products of the precipitation. The acid used may advantageously be nitric or acetic and the quantity may be equivalent to say /6 to mols per mol monobasic lead salt of dinitroresorcinol.

As a result of the addition of the acid the colour of the precipitate may become redder if the precipitate was originally yellow, and the precipitate may become denser. Using mol nitric acid the pH of the suspension containing the by-products measured at room temperature may fall from about 6.5 to 6.2.

When the precipitation is carried out by add ing the calculated amount of a lead nitrate solution to a solution containing the dinitroresorcinol and up to the calculated amount of a soluble base, especially at temperatures below 70 0., there is frequently deposited an appreciable amount of an inactive nitrogen free lead compound that is a possibly somewhat hydrated form of leadoxide. This material adheres to the base of the vessel when this is made of glass, and the monobasic lead salt of 2:4 dir 3 r 4 nitroresorcinate suspension may be decanted the procedure are the same as in Example I exand washed away from it either before or after cept that the temperature at which the precipithe addition of the acid, which in the quantity tation is carried out is 71 C. In this case the employed does. not disso1ve..the deposit. The precipitate becomes reddish even before the adlead content of the':substantiallyzmonobasic lead 5 dition 'ofntheinitric acid, but a washedwand desalt 0f2z4 dinitroresorcinol is, however, slightly hydrated samp e of e product at this sta reduced by the treatment. .gelates a nitrocellulose solution in amyl acetate The invention is illustrated by the following a While being mixed With it. The lead content Of examples. 5.1..ttfeidriedsalt-is64%. After the treatment with Example I i lfl nitrie acidphowever, the washed and dehydrated I V rsubstantiallyvmonobasic salt does not gelate the gm. 2:4 dinitroresorcinol (lemolliare'disnitrocellulose-lsolution within a week. Its ignisolved in 200 c. c. N/l sodium hydroxide solution .ntion properties .are satisfactory. The lead con- (4 mol) and 200 c. 0. water. The solution is filtent of the dried salt is 60.5%. The amount of tered andheated to 52 C. in a glass vesseL and me inactive nitrogen free lead compound adhering into it is added at a constant rate over a period tothe bottom of the glass precipitating vessel is of 12 minutes 330 c. c. of a filteredsolutiomcon- Mabout Ole-m. taining 100 gm. load nitrate per litre, the mixture being stirred and the temperature-being Example IV kept from falling below 50 C. An orange col- 0 The quantities of thegreagents for the precipioured precipitat'ei's'cfoi'me'd'g The;;:mixture :is .tatiorreare l0eg-m..-2:-$ dinitroresorcinol, 190 c. c. ool d; ndrallowe'dtoestand; .Itiisenotedrh te N/J. sodiumihydroxide .210. c. c. water-and 33O small' a-mount of-'a@yellow:.-precipitateof different 13.1 of a-solution of lead nitrate vcontainingSlOO appearance t .-.i-,he:main;portion-of the zpliecipigm leadanitratesperelitre. The-precipitation is late adheres to-ithe :bottomlof the glass vessel. Carried out win-Example I fiXceptllhat he-P The mixture is stillred-withputdjsturbing3131115, .cipitation temperature isv 11...C. The.reaction q't :it i dd d .dropwise 10 re -20% mixture...oontainingether-precipitate.which. besolution of nitric acid- This causes theemain comes i s cooled to 60 C. and'5 c. .c. 10% portion of the preci itat to i assum .a .reddish nitric e acid arev added ..dr,opwise eover I 3 minutes. colour and to densifybutedoes not appear-teat.- so Theresnlting- Washedv a d d ydralfi d' u s feet theyellgwigh:.ma,teria,1 adhering 130'v the botvfli'alllylinollobasidJeailstlt OffZ :.4.dinitroresorcinol tom oflthe-glassvessel,.whichr roves-to' befree does not gelateaflnitrocellulose solution in amyl from nitrogen-andamounts .to .0.6...-gm.J'.,lI-he acetate within a week, and yields satisfactory liquor is decanted. and thereddish .precipitateis fuseheads. The dried 'saltfhas a.lead content flushedinto-a filter, care'lbeing' taken. not to lne 6ff'61l3 Thereisnoevidence of any yellow elude any of the yellowladher ent materiaLand n c ved omp di' rin tothe'bottom is washedfree ffromisalts. It is. next washed 0f the.precip ve eL V withiacetone to'remove theYlwater' enunnany I a m with amyl acetate. 'On admixture withasolu- 7 Ajpr ss'f hep du n fantion of nitrocellul se in amylacetateitproduees 4o tially monobasic Iead saltof-ZA.dinitroresorcinol no gelation' within a week, and yieldsfuseheads inWhiCh areinclllfld p m g' p ofsatisfa'ctory quality; The lead content "o't'the "cipitate 'ofth'elead salt by'reacting asolution of a dried substantially monobasie' lead'saltofmd "disolublenor'nial leadsalt with'an alkaline solution nitroresorcinol is 63.2 of '2 :4- dinitroresorcinol -at= araisedtemperature,

In an experiment not intaccordanceiwithiire graduallyaddin h qu r c ntai n invention wherein thesamei quantities Iof" rep c p a e" formed "815111311 amount of a-d'ilute agents are 'used'and'samgprocedure adopted ex- Solution of c d Salt f which is 'ceptthat'the nitricacid treatment 'is'omitted, so l ?r m vi g--*thwdes ed--pr ipitat and the orange substantially monobasic-lead'saltof W -hmg mSdGSllBd recipitate free from he 2:4 dinitroresorcinol' obtaind'hasa lead'"content saltsformedas"by p precipitationof 66.9% and does not"flow"easilyf 'lt gelates' -a 2. '-'A-'process-as claimed in 'claim I'wherein'the solution of nitrocellulose inamyl'acetate-shortly 'a d ad salt w h s sb u is in r aitereeing mixed'intoit. 'duced dropwise intouthe liquor "containing the 7 precipitate of the monobasic l'ea'd salt of 2A a 7 Example H V .11.." d-initroresercinol and -the by-products' of theiflrst 'iThequantities of-the-reagents'employedioxethe precipitation. I precipitation-are the' sameas inrExample' l'i and 3. A processa'svclaimed tin-claim l=whereinsthe the lead nitrate solution is' added at iabout ifl" aeidgtheieleadisalt oi whichiis 'soluble,.isiinitrio cyto'thesolution containing'thetdslnitroresorcinol -.acid. l :andthesodiumhydroxide. l0fc.c.:of-l&%i acetic 00' E4.zA:processeaselaiinedzsinrclaimiliwhereinzthe acid areaddedto the cooled reactioneqnixture, acid,'the:iea=d2salt of whichiisv-soluble, riseacetic instead of 100. c. 20%anitric acidiiThiscar-ises acid. v the orange precipitate tonbecomeiredd-ishin eol- .ZAEJDLOCBSS asiclaimedi nL-claim l= whereinzthe our and denser, and-when washed'and driednthe acid; the'leadsa'lt' ofvwhich isasol'uble, is added reddish basic'lead salt :of-2:4:.d1nitroresorcino1 incaaquantity ofi irom-iabout- /e tog /sofea mole has .alead contentof 67 per. mole 'ot-the. monoi leadisalt of- :dinitroresor- -When it is =mixed-wwith a solution ofinitrocinol; cellulose inamylaeetate nogelationzoccurs with- 6:. ;-A :process for th'e production efsa substanin a week. Thefiring properties aresatisfactiallymonobasieleadsalt of-- 2-:4zdinitreresorcinol .tory. In this easel-the amour-1t pfinact'iyeyellow 7.0 which are. inchrdedr theesteps otflforming a precipitate adhering 'tO -the-bOttOln.ofrthefplepre pi a e f h l a ti ea-e vessel by cipitating es elisab utla m reacting-4a.solutionofeasoluble.normaleleadrsalt with an alkaline solution .ofszAeidinitroresorcinol e a V at a. raised temperature, -gradually adding ea --.-.f 1h e quantitiesv of .theireagentseemployed-and small amount-of a dilutesolution of. aneacidpthe lead salt of which is soluble, decanting the liquor, removing the monobasic lead salt of 2:4 dinitroresorcinate, excluding any of the precipitate of the inactive nitrogen free lead compound which is distinguishable by its color and adherence to the base of the vessel, and washing the precipitate thus removed free from the soluble salts formed as by-products of the precipitation.

LEON RUBENSTEIN.

REFERENCES CITED The following references are of record in the file of this patent:

Number Number 6 UNITED STATES PATENTS Name Date Hale et a1 May 10, 1938 Kerone et a1 Oct. 31, 1939 Rubenstein Dec. 24, 1940 FOREIGN PATENTS Country Date Great Britan Feb. 15, 1923 

6. A PROCESS FOR THE PRODUCTION OF A SUBSTANTIALLY MONOBASIC LEAD SALT OF 2:4 DINITRORESORCINOL IN WHICH ARE INCLUDED THE STEPS OF FORMING A PRECIPITATE OF THIS LEAD SALT IN A GLASS VESSEL BY REACTING A SOLUTION OF A SOLUBLE NORMAL LEAD SALT WITH AN ALKALINE SOLUTION OF 2:4 DINITRORESORCINOL WITH AN ALKALINE SOLUTION OF 2:4 DINITZORESORCINOL AT A RASIED TEMPERATURE GRADUALLY ADDING A AT A RAISED TEMPERATURE, GRADUALLY ADDING A SMALL AMOUNT OF A DILUTE SOLUTION OF AN ACID, THE LEAD SALT OF WHICH IS SOLUBLE, DEMEANING THE LIQUOR, LEAD SALT OF WHICH IS SOLUBLE, DECANTING THE LIQUOR, REMOVING THE MONOBASIC LEAD SALT OF 2:4 DINITRORESORCINATE, EXCLUDING ANY OF THE PRECIPITATE OF THE INACTIVE NITROGEN FREE LEAD COMPOUND WHICH IS INACTIVE NIGROGEN FREE LEAD COMPOUND WHICH IS DISTINGUISHABLE BY ITS COLOR AND ADHERENCE TO THE BASE OF THE VESSLE, AND WASHING THE PRECIPITATE BASE OF THE VESSEL, AND WASHING THE PRECIPITATE THUS REMOVED FREE FROM THE SOLUBLE SALTS FORMED AS BY-PRODUCTS OF THE PRECIPITATION. 